Separator for fuel cell having electrically conducting flow path part

a fuel cell and flow path technology, applied in the direction of cell components, final product manufacturing, sustainable manufacturing/processing, etc., can solve the problems of easy brittle destruction, long firing time, corrosion resistance, etc., and achieve the effect of inexpensive high-performance fuel cells and enhanced fuel cell characteristics

Active Publication Date: 2012-08-28
RESONAC HOLDINGS CORPORATION +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The solution results in a lightweight, compact, and high-performance fuel cell separator that reduces production time and costs, while maintaining excellent electrical conductivity and gas sealing without the use of additional sealing members.

Problems solved by technology

However, there is a problem in corrosion resistance.
Such a material obtained through firing as in these examples exhibits high electrical conductivity and high heat resistance, but has problems that firing takes a long time to make the productivity low or that brittle destruction readily occurs.
Furthermore, in the case where cutting is necessary, mass productivity is decreased and cost rises.
For these reasons, the material will be difficult to spread in the future.
Accordingly, the process of stacking several hundreds to several thousands of sheets takes a long time and is cumbersome.
However, although the amount of the electrical conductivity-imparting material packed needs to be greatly increased to express high electrical conductivity, reduction in the resin content is limited for maintaining moldability and sufficiently high electrical conductivity cannot be obtained.
Also, the carbon-based separator has a low specific gravity as compared with metal and can advantageously contribute to lightweighting, but when the thickness is reduced, cracking readily occurs and the reliability of gas shielding decreases.
In this way, a separator as thin as a metal separator is difficult to produce.
Furthermore, in the case of a conventional separator, as shown in FIG. 28, the flow path has a shape of symmetry from front to back and has a largely uneven thickness and when the material has a high viscosity, the processability is bad and a difference in density is readily produced between the thick part and thin part.
In the case of fabricating a fuel cell stack, a gasket or a packing is mainly used to prevent the escape of gas, but since the number of fabrication steps increases and the process becomes cumbersome, a structure not using such a gasket or packing is needed.

Method used

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  • Separator for fuel cell having electrically conducting flow path part
  • Separator for fuel cell having electrically conducting flow path part
  • Separator for fuel cell having electrically conducting flow path part

Examples

Experimental program
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Effect test

example 1

[0236]As the carbonaceous material, a non-needle coke, MC Coke, produced by MC Carbon K.K. was coarsely ground to a size of 2 to 3 mm by a pulverizer (manufactured by Hosokawamicron Corp.), and the coarsely ground product was finely ground by a jet mill (IDS2UR, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) and then adjusted to a desired particle diameter by classification. The particle of 5 μm or less was removed by air classification using a turbo-classifier (TC15N, manufactured by Nisshin Engineering Inc.). Subsequently, 0.15 kg of boron carbide (B4C) was added to a part (14.85 kg) of the finely ground product after the adjustment above and mixed in a Henschel mixer at 800 rpm for 5 minutes, and 1 kg of the mixture was sealed into a 1.5 liter-volume graphite crucible with a cover. The crucible was then placed in a graphitizing furnace with a graphite heater and after the inside of the furnace was once vacuumized and replaced with an argon gas, the powder was graphitized at an ...

example 2

[0249]As the carbonaceous material, a non-needle coke, MC Coke, produced by MC Carbon K.K. was coarsely ground to a size of 2 to 3 mm by a pulverizer (manufactured by Hosokawamicron Corp.), and the coarsely ground product was finely ground by a jet mill (IDS2UR, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) and then adjusted to a desired particle diameter by classification. The particle of 5 μm or less was removed by air classification using a turbo-classifier (TC15N, manufactured by Nisshin Engineering Inc.). Subsequently, 0.75 kg of vapor grown carbon fiber (hereinafter simply referred to as “VGCF”, registered trademark of Showa Denko K.K.) and 0.15 kg of boron carbide (B4C) were added to a part (14.1 kg) of the finely ground product after the adjustment above and mixed in a Henschel mixer at 800 rpm for 5 minutes, and 1 kg of the mixture was sealed into a 1.5 liter-volume graphite crucible with a cover. The crucible was then placed in a graphitizing furnace with a graphite hea...

example 3

[0254]As the carbonaceous material, 14.85 kg of natural graphite (high-purity natural graphite ACP, produced by Nippon Graphite Industries, Ltd., average particle diameter: 24 μm) and 0.15 kg of boron carbide (B4C) were added and mixed in a Henschel mixer at 800 rpm for 5 minutes. Subsequently, 1 kg of the mixture was sealed into a 1.5 liter-volume graphite crucible with a cover, the crucible was then placed in a graphitizing furnace with a graphite heater and after the inside of the furnace was once vacuumized and replaced with an argon gas, the powder was graphitized at an inner pressure of 1.2 atm and a temperature of 2,800° C. under a stream of argon gas atmosphere. The powder was further left standing to cool in an argon gas atmosphere and then taken out to obtain 0.93 kg of Graphite Fine Powder (A3).

[0255]Thereafter, 50 mass % of Graphite Fine Powder (A1) produced in Example 1, 35 mass % of Graphite Fine Powder (A3, natural graphite), 13.2 mass % of polypropylene (SunAllomer (...

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Abstract

A high-performance separator for a fuel cell is provided that includes an electrically conducting flow path part and an integrated insulating outer circumferential part surrounding the flow path part. The flow path part includes an electrically conducting resin composition including a carbonaceous material (A) and a thermoplastic resin composition (B) at a mass ratio (A) / (B) of 1 to 20 with the total mass of (A) and (B) accounting for 80 to 100 mass % in the composition. The flow path part has a corrugated shape having a recess and a projection on each of front and back surfaces thereof, where the recess constitutes a groove for a flow path, and a thickness of 0.05 to 0.5 mm and a maximum thickness / minimum thickness ratio of 1 to 3. The insulating outer circumferential part includes an insulating thermoplastic resin composition having a volume resistivity of 1010 Ωcm or more.

Description

TECHNICAL FIELD[0001]The present invention relates to a fuel cell separator comprising an electrically conducting resin composition, which is excellent in electrical conductivity and mechanical characteristics, is lightweight and compact and enables the construction of a fuel cell stack without using a gasket or packing, and also relates to a single cell unit for a fuel cell and a short stack unit for a fuel cell, each using the separator, and production methods of a separator for a fuel cell and a cell unit (single cell unit or short stack unit) for a fuel cell.BACKGROUND ART[0002]In recent years, from the standpoint of environmental issues and energy problems, fuel cells have been attracting attention. A fuel cell is a clean power generating device which generates electric power by a reverse electrolysis reaction of water using hydrogen and oxygen and discharges only water, which is classified into several species according to the kind of the electrolyte and among these, a solid p...

Claims

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Application Information

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Patent Type & AuthorityPatents(United States)
IPC IPC(8): H01M4/64
CPCH01M8/0213H01M8/0221H01M8/0226H01M8/0228H01M8/0254H01M8/026H01M8/0267H01M8/0273H01M8/0284H01M8/242H01M8/0263Y02E60/50Y02P70/50H01M8/02B82Y30/00
InventorIINO, TADASHIIZUMI, ZENICHIROTANAKA, YUKIHITOKAWAMURA, TOSHIKI
OwnerRESONAC HOLDINGS CORPORATION